Apollo 16: A ride up Stone Mountain

Fifty years ago, April 22, 1972: The Rover and John Young on the slopes of Stone Mountain.


“OK, Houston.  We’re underway.”  It’s shortly after noon, Eastern time on Earth, April 22, 1972, and after 52 min. saddling up our Rover, we’re heading out, the long drive to Stone Mountain, where we still hope to find volcanic rocks, of a variety called the Descartes formation.  We’ll be cross the rays of ejecta from South Ray Crater and sampling those too, later on our 7-hr. EVA.  We’re a couple minutes late out of the gate, but rolling.  And rolling is the word through this highlands world of rocks, boulders and craters upon craters.  

Heading south — on the ray which is “just covered with blocks and holes.”    We’ve gotta swerve this way and that to avoid the bigger rocks and blocks.  And now and then the back wheels break loose in the soft dirt.

“Yeow!  Whoo!  Man, that was a great big skid.  We’re doing 10 clicks, Tony.”  Clicks means kilometers per hour, and ten is our top speed.  Tony is science-astronaut Tony England, our Capcom in Houston.   

“We’ve gotta get out of this,” I say.  Too many rocks and blocks we’re weaving through in this area.

We’re generally heading down a slope towards the mountain.  We’re gonna climb about a third of the way up the dome-shaped, 1,600 ft. tall mountain.  We’re aiming for five craters call Cinco up there on the mountainside. 

“Tony, apparently this ray is pretty extensive.  We haven’t got out of this cobble field yet.”  We’ve driven about 8 min. so far, a half mile into our 2.6 mi. drive.  A decrease in rocks will signal that we’ve left the ray’s ejecta.  “Oh, man, John,” you say.  “This is really a ray; it just goes right in to South Ray.”

Five minutes later, I observe, “We must be coming to the edge of it.  My estimate of the cobbles is back down to about 20 percent now.  We have secondaries within secondaries.”  Meaning secondary craters formed by debris tossed from the South Ray impact.  We’re now a mile-and-a-quarter from our Lunar Module, Orion.

“Boy, isn’t this something?” you say as we bounce along.

I laugh, “This is really something!”

The number of rocks continues to decrease, we start up Stone Mountain.  We see no obvious transition in the surface material when we reach the mountain and start to climb.  We’re about 2 mi. from Orion. 

“Hey, that was super.  That wheel just left the ground.”

I laugh again.  “This is the wildest ride I was ever on.”

We climb a steep rise and keep on.  “We’re really going uphill!”

We go on up to one of the Cinco craters.  The drive has taken 36 min.  “We’re certainly up in the air!”

We’re at “Station 4.”  Each planned worksite has been given a number.  We’re 575 ft. up the mountain on a steep slope of 20 degrees.  indeed, I’ve had to park in a small crater so the Rover isn’t in danger of sliding.  We begin to work at a rock pile, a jumble of all sizes.  Talk about a rock field! 

Tony calls, “Could you give us a general impression of the rock types?”

He’s eager to know if we’re seeing anything volcanic.  But I report, “It looks to me like this rock pile that we’re seeing in there is the same type of rock.”  Angular.  Those darn breccias.

Tony says, “You think you’re getting breccias there, then?”  

You hop upslope to start work.

“OK, let’s not go too far,” I caution

“I’m not.  It’s pretty steep.  If you jackrabbit up it, it’s pretty easy to do.”  We really kick up the dirt going uphill, our feet slipping a bit with each step.  We’ll sample what we can.

We’ve been given 50 min. here; it was to be our prime site.  You observe, “I wish we could say these rocks look different but they don’t.”   And all the rocks on this steep slope seem to have been blasted from South Ray Crater, which we intend to explore tomorrow.  Quite a view of everything from up here, across our landing site to Smoky Mountain and North Ray Crater.  “Wow!  What a place!”

Tony suggests, “Bring up the rake and maybe we’ll get some Descartes” material.

You use the rake, hoping it’ll sift out small pieces of volcanic rock.  Fifteen fragments, you announce. “I don’t think these are pieces of rocks.”  Damn — they crumble, more like dirt clods.   

.  I go uphill to one of the Cinco craters that may have lifted bedrock (volcanic!) samples from the interior.  In a couple minutes I reach the fairly fresh (meaning sharp definitions that indicate its relatively young) 80-ft. crater.  I reason that we’re more likely to find bedrock not contaminated with material from South Ray on the shielded western side of the crater.  Alas — I see no bedrock.

You take telephoto pictures of South Ray out there on the plain below us.  What a view of it — its bright ejecta splashed over it’s raised rim and fanning out in a perfect circle.  It’ looks as if the object that created it had just impacted. 

Tony calls, “We’d like you to pack up.”

Maybe we’ll have better luck further down.  Tony reminds us, “What we’re looking for is a primary.”  A primary impact (not a secondary from South Ray) that may have drilled down into bedrock.

Farewell, Cinco.  We drive down the mountain, fast.  Downhill is easy!  “Ya-ho-ho-ho,” I yell.  “Look at this baby.  I’m really getting confidence in it now.  It’s really humming like a kitten.”  We keep an eye out for a crater with a blocky rim.

“How about this one right here, Charlie?”

“Yep, that’s it, John.  That’s a good one.” 

The trek down the mountain takes just 5 min.  Call this Station 5.

Tony wants us to look for rounded rocks.  “The angular boulders are probably from South Ray.  And maybe the rounded ones are working their way out of the regolith here.  So that may be a clue to our getting Descartes.”

“Good point.”

And I say, “If we do a rake sample in the wall, would probably be our best bet.”

I see a small crater, could be a primary impact in the larger secondary crater we’ve chosen.  We take out the ol’ rake.  But the fragments fall apart — clods.

Tony says, “Maybe the next one will be Descartes.”

Looking over our chosen crater, “The only rocks we see are angular here on the rim.”

We slip slide down inside the rim — a big shallow crater, almost like an oversized golf sand trap.  

Hey — we find some rounded rocks, whitish.  Yes, more rounded than South Ray rocks.  

Tony calls, “We’d like you  to stay inside the rim and work your way around and see what you can find.”

It’s so soft inside here, sometimes we’re treading dirt.  “You really feel like you’re on the edge of instability.”   You said it, Charlie.  I can see how you bounce your legs to find your balance, dirt slipping from under your boots.  You follow me around the inside rim.  With each step, we slip down about a couple inches.  

“There’s a round one, Charlie.”  We find more that look crystalline rock.

I surf the dust on the steepest slope, hopping up it. rake out in front of me, held high against the wall.  Figure Descartes material might be high on the wall.  But it looks the same as all the others.

Tony calls, “And we’re going to have to press on after this sample.”

I cautiously walk around the rim to the Rover.  You bounded straight across the crater and up.  “That was fun!”

We finish out our time here near the rover.  I work the portable magnetometer.  And find a beautiful example of a greenish crystalline rock.   It’s shaped almost like the head of a rattlesnake, and becomes known as the Diamondback Rock. 

“John, that is the best samples we’ve gotten.  That is a great rock.”

And, after 48 min., it’s time to move on.  We’re not quite half through our EVA.

As we pull out, Tony calls, “And we would like Station 6 at the lowest terrace on Stone Mountain and a blocky crater, if possible.”  

We drive for 8 min., down and around, and find it, a shallow 65-ft.-diameter crater.  “I think it’s a secondary.”  Maybe it punched through to the bedrock.  We take samples, whacking pieces off the hard boulders, not sure if they’re breccia.  We only take only 23 min. here, but it turns out very productive — we find some fine-grained crystalline rock, the kind we’re after, pristine rock.

We’re skipping Station 7, as it’s close to Station 8.  Off we ride, with you giving commentary as I concentrating on driving.  “We’re still in a blocky field.  In fact, it’s just South Ray material, I think, that’s all over the place.”

“OK, we’re back into the thicker part of the ray, Tony.  The regolith here is covered with cobbles, about 40 to 50 percent.  You’re gonna have to bear way left, John.”  Station 8 is on a ray, just past a crater we’ve named Wreck.  We’re riding ridges now.  “John, why don’t you swing directly south and let’s just go straight up that beauty, see what we see up there. Probably nothing but another ridge.”

“It’s pretty steep, Charlie.”

We slow way down.  “Have you got it on full throttle?”

“I got full throttle.”

“Boy, we’re hardly moving.”

Then by the readouts, I see what happened.  “OK, what it is, is we’ve lost the rear-wheel drive.”  We’re still 2 mi. from the LM.  It’s walkable, if we lose the Rover.  Not recommended.  

Well, the Rover is still operating on the front-wheel drive, able to do 7 kph on the flat.  We stop in the middle of some boulders, probably the South Ray material we’re after, and call it Station 8.

We take a rake sample in a shallow crater.

“There’s a boulder we can split, ” I say.

“That one off to you right down there.  I think we could turn that one over.”  We want to roll a rock over to sample the shielded underside. But this one is too big.  You hammer away at the small boulder and drop the hammer.  

“That’s all right, Charlie.  I do that all the time.” 

You bound by it, dip down — try to pick it up.  Can’t nab it.  Have to go get the tongs to pick it up.  That hammer keeps you working, bustin’ your hands — you’ve gotta drive a core tube in the ground.  And the ground proves hard.  That hammer keeps slipping, turning, falling.  It’s hard to hold in our gloved hands, gives them a beating until they throb and ache.  

While you’re doing that, I do some solo sampling.  I decide to give the Rover a little test drive to another sample area.  And I see that one of the switches is out of position, musta been jarred when we got on or off the Rover.  I tell Houston, “That’s the problem!  Somehow this guarded switch got moved . . .  Oh, isn’t that Amazing.”

On we go — chipping at another low 6-ft.-long boulder, that proves too big to turn over.  At a fracture in it, I can almost pry a chunk off with my hand.  Gotta get out the ol’ hammer, though.  That does it.

“Man, the whole rock is coming apart.  Super job, John.”  And you say it looks crystalline to you.  “That’s no breccia.”

We take chips off more boulders. As I beat on one, you comment, “That’s a hard breccia, ain’t it?

“A hard, hard rock.”  I don’t even want to speak the word breccia.

Tony tells us, “OK, your consumables look pretty good.  In fact, you may even be able to get a little extension.”


Our big sample containers, holding all the bags of samples, are full.  We have to change them out.  And, man, it’s taking time.  Too much time — a terrible waste of time, I say.

“We’ve been here an hour,” you point out.

I’m working at the Rover with the sample containers.  Start to move around from your side of the vehicle.  I’ve got my hammer in my leg pocket and at the rear wheel. . .  “There goes the fender.”  I’ve caught it on my hammer — and the lower extension breaks off.

“Uh-ho,” you said.  And that’s the word for it — because from now on, that wheel will toss a rooster tail of dust, showering us in moon dust.   Dust, dust, dust — that’s our story.

On we go — Station 9, just a 5 min. drive, closer to the LM.  Not as many rocks strew about, but I see a knee-high boulder that suits my purpose.  “That rock over there — the one I want to sneak up on.”

That”s what we call it.  Our goal is to sample dust on and around it, without contaminating the sample undisturbed by us.  We want to creep up to it making sure not to kick up the least bit of dust on it.  A pure, uncontaminated sample.  

“John, are you sneaking?”

“Yes.”  I carry a special container designed to trap the dirt.  I make my move.  “Gotcha!”

You joke, “He really got up to it before it knew he was coming.”

And then I turn it over.

“He did it, Houston.  He did it!”

And Tony chimes in.  So you can not only sneak up on them, you can flip them over, huh?”

“Yeah, that’s a biggie,” I say  ” . . .Look at that soil underneath!”

I take a chip off the bottom and soil samples from the deepest spot it penetrated.  We’d planned to spend  25 min. here, but we end up staying 40 min.  We’ve been outside for about 6 hrs.

We’ve got one more brief stop, at the ALSEP site before coming home.  Houston asks you to run some penetrometer tests.  The staff-life penetrometer, when pushed into the ground, measure the consistency of the soil.  It’s work — as you push in all the way down, nearly going prone.

It takes time, too, and you ask, “Why don’t you just give us an extension?”

“We’d like you to get back in on time.

“How about 10 min., Tony, please.”


“OK, we’ll go ahead and give you 10 min.”

“An attaboy for Flight!” 

Of course, we have to leave time for a 40-min. closeout at the LM. 

As you walk by the ALSEP, taking final penetrometer readings, you sigh, “Poor old Heat Flow.”

Tony hurries us now.  “We’re going to have to pack up and head home.”

“Home is about 50 meters away,” you say.  And you jog home, skipping along.

At the LM, we pack up all our samples.  “Man, we got a lot of rocks.”

And we also note that morning on the Moon is getting later.  “That shadow is getting short” — the shadow of the LM.

We end our moonwalk after 7 hrs. 20 min., a record time.  And I’ll tell ya, we’re almost out of oxygen by the time we get inside.  We cut it a bit close there!

As we prepare for our second sleep on the moon, Tony tells us, “I know we didn’t see what we expected to see, but we think you got everything that we went for.”

Yep — the ol’ moon defied expectations.  They’re gonna have to throw out that book on volcanism in the highlands. 

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